Engines with cooled components, such as gas turbine engines, are often improved by altering different characteristics of an engine or its components. Some examples of alterable features include the weight of one or more components, the engine efficiency, and the cost of manufacture of the components or overall engine system. It is typically difficult, though preferable, to improve simultaneously as many aspects as possible.
Frequently, tradeoffs are made to produce different engines containing different characteristics, as desired for a particular purpose or role. As one example, an engine can often be designed with greater efficiency and reduced cost, but resulting in a higher engine weight. Similarly, an efficient, light-weight engine can often be made at a higher cost.
A turbine engine's performance can depend, among other things, on the ability to cool components, such as airfoils, to permit them to operate at higher temperatures. While this typically is done at the expense of another desirable engine characteristic or feature, it would be advantageous for an advancement to improve simultaneously one or more aspects of an engine without returning the benefit through a tradeoff.
One technique of improving heat transfer efficiency within an engine is to form divots, bumps, or holes in the surface of a component, increasing its surface area, and/or permitting the passage of gases through the component. To form such features, processes such as laser drilling or machining can be used. This can be expensive, and often increases the cost of the engine beyond any improvement from the increased efficiency. As another technique, some components can be cast. Disadvantageously, though cheaper, casting for fine holes or surface features often results in poor quality components, increasing the reject rate and cost.